1. Field of the Invention
This invention relates in general to high performance heatsink designs to improve the thermal management in high power dissipating and high performance electronic circuits.
2. Description of the Related Art
As circuitry in electronics becomes more complex, thermal management of the circuitry has become more difficult. The common method for cooling electronics has been to use either forced air convection through heatsinks or to use methods which incorporate heatpipes or vapor chambers. The latter methods have been to date fairly expensive relative to common aluminum or copper based heatsinks. Until recently, thermal management of high performance electronics has been manageable without the use of such expensive and elaborate thermal devices, such as heatpipes, due to the low power consumption of the electronic devices. However, the recent insurgence of the power requirements for electronics, such as microprocessors, has dictated that larger and more elaborate thermal solutions become necessary.
More recently advances in silicon fabrication techniques have permitted the manufacturer of high performance IC packages with operating voltages at or below 1 volt and power levels in excess of 100 watts. Additionally, the size of the IC dies have shrunk which has increased the thermal density or heatflux through the thermal interfaces to the heatsink. This has had a two-fold negative effect in that not only has power increased, which has often necessitated a larger heatsink, but the thermal density has increased also requiring better thermal conduction through to the fins of the heatsink enabling heat to be more efficiently extracted via forced convection through these fins. One method to mitigate the heat flux density problem somewhat is to improve the lateral conductivity of the heatsink base enabling better thermal transfer to the fins. However, moving to vapor chamber or heatpipe or higher thermal conductivity base material and designs to more efficiently transfer heat to the fins is more costly than using standard heatsink materials such as aluminum and copper for heatsink designs. Alternatively, one may increase the airflow through the heatsink thus improving the rate of heat transfer through forced convection. However, this increases the burden at the system level air moving devices and often the increase in larger fans or blowers and sheer volumetric space to accommodate these larger devices is prohibitive. Thus, it is seen that there is a need for a new heatsink technology that not only uses standard heatsink materials, such as aluminum or copper, but also is more efficient in the conduction and convection paths thus resulting in a more efficient design overall.
To address the requirements described above, the present invention discloses a method and apparatus for cooling a heat dissipating device. The apparatus comprises a fin array having a plurality of fins and having a variable fin density, the fin array including a first fin array region proximate to and in thermal contact with the heat dissipating device; a second fin array region distant from the heat dissipating device. The first fin region includes a first fin density and the second fin region includes a second fin density less than the first fin density.